Thermoelectric motor



June 1951 c: B. GUAJARDO 2, 8 2

THERMOELECTRIC MOTOR Filed Sept. 24, 1948 2 Sheets-Sheet l 9 v Suvmior 2a a j Cz'rafiGuajardo 40 u fia l r 3 I i g" M (Tirol-lugs June 1951 c. B. GUAJARDO THERMOELECTRIC MOTOR 2 Sheets-Sheet 2 Filed Sept. 24, 1948 Zhwcnkor F5; 6- Cz'robfmy'ardo Patented June 5, 1951 UNITED STATES PATENT OFFICE THERMOELECTRIC MOTOR Ciro B. Guajardo, Kenton, Ohio Application September 24, 1948, Serial No. 50,914

3 Claims.

My invention relates to thermo-electric motors, which consist essentially of an elongate electric resistance element connected to a movable member in such manner that the resistance element, expanding and contracting alternately when heated by an intermittently applied electric current, produces motion in said movable member. The movable member is connected to the apparatus or device which is to be driven by the motor.

More particularly, my invention consists in certain new and useful improvements in thermoelectric motors of the type indicated, motors which are particularly, though not exclusively, designed for advertising displays.

In the advertising art it is desirable in many cases to provide displays which consist of placards displaying or representing the goods or things to be advertised. This type of display has been found to be much more attractive if a moving element is presented adjacent to or on the face of the placard. Heretofore, electric motors costing several dollars each have been used to drive movable elements associated with advertising placards, but in view of the fact that each placard is replaced periodically, in order to feature new displays and maintain the attention of the public, it has been necessary to service the displays with skilled mechanics, who salvage the electric motors from the discarded placards and incorporate them in the new displays.

My invention stems from the concept that, if an electric motor be produced at a cost of ten cents or less per motor, the need for skilled mechanisc in changing displays will be eliminated. A motor of such small cost may be permanently mounted upon each placard, with the effect that it becomes economically feasible to throw away the motor along with the placard. That is to say, it is merely necessary to remove the placard to be dispensed with, and to substitute a new one for it.

The motor of my invention affords advantages of th nature indicated, and others which will be apparent in the ensuing specification.

Referring to the accompanying drawings an embodiment of the invention is illustrated:

Fig. 1 is a view in front elevation of an advertising display which depicts a man driving a bung in a barrel. The arm of the man holdin a mallet is pivotally mounted upon the face of a placard bearing the representation, and on the back of the placard a motor of the invention is arranged to oscillate the arm of the man, thereby affording a vivid representation of the action intended;

Fig. 2 is a view in vertical section of the placard, as seen on the planes 11-11 in Fig. 1. In this case the placard is compound, with the figure of the man and of the barrel spaced from the main body of the placard, whereby the pivotal mounting of the arm of the man may be screened, as indicated;

Fig. 3 is a view on smaller scale showing in detail the structure of the electric motor, as seen from the rear of the placard;

Fig. 4 is a wiring diagram, illustrating the electric circuit and means for intermittently energizing the motor;

Fg. 5 is a diagrammatic view of a modified form of the motor of the invention; and

Fig. 6 is a view diagrammatically illustrating means for increasing the range of travel of the driven element of the motor, without increasing the overall dimensions of the motor.

Referring to Figs. 1 and 2 of the drawings, the reference numeral 2 is applied to a placard formed of paper board, which is provided with two rearwardly extending wings 3, whereby the placard may stand erect upon the floor of a store window, or other support for display. Spaced at an interval from the face of the placard 2 is a second planular member of paper board, fashioned in the outline of a man 3 and a keg or barrel 4. This second paper board member (3, 4) is secured to the placard 2 by means of channels 5 and 6, formed of paper board glued or cemented in place. In this case the display is intended to represent a workman driving a bung 5 in the barrel, and for this purpose the arm I of the man, holding a mallet 8, is pivotally mounted for oscillating movement. It will be understood that the display may constitute the advertising medium for a whiskey or malt beverage producer, and that the desired legends may be printed or otherwise applied to the face of the placard 2. The invention consists in an improved thermoelectric motor designed in this case to oscillate the mans arm 7, and this structure will serve to illustrate the general field of utility of the motor.

Referring to Figs. 2 and 3, it will be understood that the motor consists of a simple frame or basal element 9 which is adapted to be secured upon the rear surface of the placard 2, as by means of bolts or rivets It, or by means of a suitable cement. A shaft or spindle II is mounted for rotation at the upper end of the basal member 9, and is arranged to extend through the body of the placard 2 to provide the pivotal support for the arm I of the man. Collars l2 and 13 are secured to the spindle as shown in Fig. 2, to prevent axial displacement thereof. The arm 1 of the man is fixed to the projecting end of the spindle, and it will be noted that the so-piloted end of the mans arm is located between the body of the man and the face of the placard, where it is hidden from the view of a person observing the display.

The upper end of the basal member 9 of the motor is formed into a loop [4 that provides an additional support and bearing for the spindle II, as indicated at l5. The spindle extends outwardly from the bearing I5, and provides a drum portion I6, upon which the upper end of a strand I"! of electrical resistance material is wrapped, as indicated at l8. The otherwise free upper end of the strand is anchored to the spindle by means of a set screw [9 threaded in a collar 29 fixed to the spindle. The lower end of the strand is anchored to a rigid support 2| carried by the basal member 9 and electrically insulated therefrom, the attachment of the strand to the support 2| being effected by means of an adjus able screw 22.

A circuit wire 23 is electrically connected'to the basal member 9 of the motor, and such basal member, being formed as it is of metal, provides through the body of the spindle II which it contacts electrical union with the upper end of the strand H. A circuit wire 24 is connected to the support 2|, which is electrically insulated from the basal member 9, and provides electrical union with the lower end of the strand 11. Therefore, it will be understood that the strand I1 is included in an operating electrical circuit, and that by intermittently supplying electric current to the circuit current may be caused to flow intermittently through the strand [1.

The strand I1 is formed in this case of a fine wire of stainless steel, a wire having a diameter of approximately .003 of an inch, but it is to be understood that electric resistance elements of other compositions may serve, the invention being principally directed to the mechanical organization or construction of the motor rather than to the particular composition or form of the resistance strand which may be used.

The intermittent energizing of the circuit wires 23 and 24 results in the strand I! being alternately heated and allowed to cool. As the strand I1 is heated it increases in length, whereby the spindle ll rotates under the effect of gravity acting upon the mans arm I, and in consequence the mans arm moves downwardly, giving from the front of the display the representation of the man striking a blow upon the bung of the barrel. The succeeding interruption in the flow of current through the circuit wires 23 and 24 allows the stand I! quickly to cool and to contract, with the result that the spindle II is rotated in the direction to raise the mans arm. Thus, it will be understood that the intermittent delivery of current through the circuit wires 23 and 24 is instrumental in effecting the alternate raising and lowering of the mans arm I, and the desired representation of the man driving the bung in the barrel is produced.

The downward swing of the mans arm 1 under the effect of gravity may be positively limited, if desired, as by means of a finger 25 extending from the collar I3 on the spindle H, such finger being arranged to engage the body of the basal member (or the loop portion [4 thereof) as indicated at 26 in Fig. 2.

In this case the thermo-electric motor mounted on the placard 2 may be enclosed within a housing 21 of paper board, with suitable. vents formed therein to provide the necessary circulation of air required to permit the rapid cooling of the strand I! in the intervals between the flow of electric current through the circuit wires 23 and 24.

The invention includes in combination with the structure above described means for effecting the intermittent flow of current to the circuit wires 23 and 24. As shown in Fig. 4, an electric supply circuit 23 is arranged to energize the circuit wires 23 and 24, and the connection to the electric supply circuit may, it will be understood, be eifected by means of a well known plug-in socket. Between the circuit wires 23 and 24 and the electric supply circuit 29 a transformer 30 is arranged, in order to provide the proper reduction in the potential of the supply circuit (say volts) to the potential required in circuit 23 and 24 for the operation of the motor (13 volts in this case). Between the supply circuit 29 and the transformer 30 there is arranged an electric inter rupter 3|, which is adapted automatically to make and break the electric flow of current to the transformer at the frequency required for the operation of the thermo-electric motor. The electric interrupter comprises a bi-metallic element 32 mounted at one end on a fixed support 33 of insulating material, and equipped at its distal end with an electric contact 34. In opposition to this bi-metallic element a conductor bar 35 is secured to the support 33, and is equipped at its distal end with a contact 36. One terminal of the primary coil of the transformer 30 is connected by a wire 31 to one wire of the supply circuit 29, while the other terminal of the primary coil of the transformer is connected to the supply circuit by means of a wire 38, which includes the bi-metallic element 32 and the con ductor bar 35.

The bi-metallic element 32 tends to remain in the open position in which it is shown in Fig. 4, with the contacts 34 and 36 disengaged. In or der to close the contacts 34 and 36 as required, a high-resistance coil 39 is wrapped upon the bimetallic element 32 and shunt-connected across the points at which such bi-metallic element and the conductor bar 35 are connected in the circuit wire 38. The coil 39 is a resistance heating coll. When the contacts 34 and 36 are open (Fig. 4),- the coil 39 is connected in series in the circuit 29, 31, 38, and as thus connected in series with the primary coil of the transformer there is a relatively small but adequate flow of current to heat the resistance coil 39. However, this flow of current in the primary coil is insufiicient to induce in the secondary coil of the transformer a current at a potential which will overcome the resistance of the strand IT connected in series with said secondary coil; that is, when the heating coil 39 is connected in series with the primary coil of the transformer the current induced in the secondary coil circuit 23, 24, IT is negligible. As the coil 39 in said series connection develops heat the bi-metallic element 32 is deflected downwardly and closes the contacts 34 and 36, with the result that the coil 39' is shunted and a major flow of current is effected through the primary coil of the transformer. motor-operating flow of current is induced in thesecondary coil of the transformer and such cur rent flows in the circuit wires 23 and 24. This majorfiow of current through the members 32' and 35 robs the coil 39 of sufficient current to heat it, with the result that in a short interval In consequence, a

into open position, thereby breaking the electric union of the contacts 34 and 36, and interrupting the flow of operating current through the circuit wires 23 and 24. Immediately, the coil 39 begins to heat again, and in a matter of seconds the bi-metallic element 32 is again deflected, and again closes the contacts 34 and 36. Thus, energy delivered to the primary coil of the transformer 30 is controlled in a manner to provide the desired intermittent energizing of the circuit wires 23 and 24, which in turn efiects the desired alternate elongation and contraction of the strand I1.

The transformer 30 and the interrupter 3| connected thereto, as shown in Fig. 4, will be understood to comprise a permanent installation at each location where an advertising display is to be mounted, wherefore in order to install or remove the advertising display it is merely necessary to connect or disconnect the circuit wires 23 and 24 at the terminals 40 and 4|, Fig. 2.

The motor mounted upon the placard 2 may be manufactured at relatively small cost, with the effect that it becomes economically feasible and advantageous to discard the motor along with the rest of the display, as mentioned in the introduction of this specification.

In Fig. 5 a modification of the motor apparatus of the invention is illustrated. The basal member 9a of the motor provides a pivotal support for an arm IIa. The strand I'Ia of electric resistance material is at one end connected to the arm Ila, and at opposite end is connected to a fixed support 2 Ia insulated from the basal member. A tension spring 42 is connected to the arm Ila at the same distance from the pivot Ilb of the arm as the strand Hat is connected. The tension of the spring is adjustable, as by means of the take-up device 43, and the tension of this spring serves to maintain the strand I'Ia taut, in the same general way that gravity acting on arm I in the structure first described tends to rotate the spindle II and maintain the strand II under a slight but sufiicient tension. Circuit wires 23a and 24a connect the secondary coil of transformer 30a to the opposite ends of the strand I'Ia, and the interrupter 3 la in the circuit between the supply circuit 29a and the primary coils of the transformer operate, as in the structure first described, intermittently to energize the strand I'Ia. The strand alternately expands and contracts, and this action, coupled with that of spring 42, operates to oscillate the arm Ila. The distal end of this arm may be suitably connected to the member or mechanism to be driven.

Among other things the modification illustrated in Fig. 5 discloses that spring tension may be employed in lieu of gravity to cooperate with an expanding and contracting strand, to produce the desired motion in the motor.

In case the range of expansion and contraction of the strand (H or I'Ia) is required to be greater than can be conveniently obtained by a single reach of the strand, Fig. 6 serves to illustrate that the reach may be increased without increasing the given or specified distance between the fixed support 2Ia and the arm IIa. This efiect is obtained by providing on the basal member two pulleys 44 and 45 of high heat insulating material, such as asbestos, or a plastic material, such as Bakelite. The strand He is trained over these pulleys in its extent between the support 2 Ia and the arm Na, and the efifect of a strand of almost triple length is realized.

Manifestly, this feature may be utilized in the motor of Figs. 2 to 4, as well as in the motor shown in Fig. 5.

Various other modifications are held in con templation within the spirit of the invention defined in the appended claims.

I claim:

1. Electrical apparatus comprising a thermoelectric motor including a basal member, a driving member borne by said basal member for movement in alternate directions, yielding means for moving said driving member in one of said alternate directions, a support portion on said basal member, a strand of electric resistance ma terial connected between said driving member and said support portion, said strand being expansible under the flow therethrough of an operating electric current for releasing the driving member for movement under the effect of saidyielding means, said strand being contractible upon an interruption of operating current flow for moving said driving member in the other of said alternate directions, an electric operating circuit, a transformer arranged in said operating circuit with its primary coil for connection to an electric supply circuit and with its secondary coil connected to said strand, a pair of electric contacts in said operating circuit on the primary coil side of said transformer, a bi-metallic element for moving said contacts between circuitclosing and circuit-interrupting positions, and a heating coil connected in said operating circuit for deflecting said bi-metallic element into circuit-closing position when said contacts are open, said contacts being arranged, upon moving into circuit-closing position, to shunt said heating coil whereby the bi-metallic element restores said contacts to circuit-interrupting position.

2. A thermo-electric electric motor apparatus comprising a relatively narrow, elongate basal member having a support outstanding adjacent each of its opposite ends, a driving member comprising a spindle borne for rotation in opposite directions in one of said supports, yielding means for rotating said spindle in one of said opposite directions, a drum portion on said spindle, a strand of electric resistance material secured at one end to the other of said supports and at the opposite end wrapped upon said drum portion, said strand being expansible under the fiow thereof of an operating electric current for releasing said spindle for rotation in one of said directions under the effect of said yielding means, said strand being contractible upon an interruption of operating current fiow thereto for rotating said spindle in the opposite of said directions, an electric operating circuit including said strand, 2. pair of electric contacts, a bi-metallic element for moving said contacts between circuit-closing and circuit-interrupting positions, and a heating coil connected in said circuit for deflecting said bi-metallic element into circuit-closing position when said contacts are open, said contacts being arranged, upon moving into circuit-closing position, to shunt said heating coil whereby the bimetallic element restores said contacts to circuitinterrupting position.

3. A thermo-electric motor apparatus comprising a relatively narrow, elongate basal member having a support outstanding adjacent each of its opposite ends, a driving member comprising an arm, a pivot securing said basal member at a point intermediate said supports, an adjusting screw mounted in one of said supports, a spring connected between said screw and said arm and tending to swing said-arm in one direction to rotation on said pivot, a strand of electric resistance material extending from the other of said supports and connected to said arm at a point substantially nearer to said pivot than to the distal end of the arm, said strand being expansible under the flow therethrough of an operating electric current for releasing said arm to swing in one direction under the effect of said spring, said strand being contractible upon an interruption of operating current flow therethrough for swinging said arm in opposite direction, an electric operating circuit including said strand, a pair of electric contacts, a bi-metallic element for moving said contacts between circuit-closing and circuit-interrupting positions, and a heating coil connected in said circuit for deflecting said bi-metallic element into circuitclosing position when said contacts are open, said contacts being arranged, upon moving into circuit-closing position, to shunt said heating coil whereby the bi-metallic element restores said contacts to circuit-interrupting position.

CIRO B. GUAJARDO.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 952,778 Wohl et a1 Mar. 22, 1910 996,224 Dennis June 27, 1911 1,925,360 Altemiller Sept. 5, 1933 2,317,630 Menzies et al. Apr. 27, 1943 

